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Its def not a bad read. I though that too at first but thats 100% retested like a dozen times and even verified a bunch. its verifies perfect. Got that from the memcal adapter and then checked it against a direct EPROM read and it verified there too. It does look weird though, maybe it was originally a bad write?

Maybe yeah .I dunno ant is the one who can spot 1 missing address pin as a pattern lol

Got it to work this time. I selected the AMD 27C128 instead of the generic one and it seem to have red fine this time. IDs as $A5 VN V6.

I think some of the factory EPROMs were AMD but I could not work out what make this one was hence why I initially used the generic one.

It appears to be a bone stock ASBY tune which is SV3800 tune iirc I did a compare and only 3 bytes differ, date codes and production sequence. I had a look at the AFR table, lol wow HSV literally were doing it ass about. its terrible.

It does indeed seem to be ASBY.

I'm surprised that's a SV3800 tune 'cos it sucked for performance & very ordinary at low speeds/light throttle situations...did have decent economy though but a tonne of holes in that tune.

Kept the spare ATFY(?) vn memcal in ute as it drove nicer although runs richer.

gtrboyy wrote:I'm surprised that's a SV3800 tune 'cos it sucked for performance & very ordinary at low speeds/light throttle situations...did have decent economy though but a tonne of holes in that tune.

Kept the spare ATFY(?) vn memcal in ute as it drove nicer although runs richer.

yeah the AFR table had values of 14-15:1 up to full load in low areas, also the timing was only 4º at full throttle under 1600 rpm or so, then jumped to about 9 in the next row. Then at high rpm full throttle the AFRs were at flat 12, so it would be pig rich, so poor performance everywhere compared to whats achievable.

In your new tune its done right and I have also filled in areas in the cruise parts of the map to be 16:1 all of the time then disabled lean cruise. So this basically forces a conservative lean cruise all of the time. Factory used 17:1 which is too lean and ends up loosing torque and actually then uses a little bit more fuel. 15.5-16 is where I found best.

You have to remember that HSV never aimed to achieve max power/torque only a bit more than what Holden put out.

Maybe your're looking at something different to me but I think that your description isn't really a true representation of the ASBY tune.

For those playing along at home this is the standard ASBY tune Vlad, do you want to post up the tune you have done, I'd be keen to see it.

yeah it should be in the custom tune section. let me see if I can find a link

I think I mistaken the row in the spark map as 12P has many more than the factory VN/VP ones. Anyway I put about 9º at the top right cell iirc

You can see the AFR table is pretty bad, the factory one is better, too lean up in the mid/mid-high and very high ends its too rich.

EDIT: couldn't find my tune in the custom tune section. I also have it in my build thread but hard to find with FB pics all missing. So I will post up a pic of the 2 tables later.

here we go.